The extraction and analysis of tissue samples has proven a highly effective procedure for identifying cancer, premalignant conditions and other pathology. This procedure has proven particularly effective for identifying pre-invasive cervical lesions, the treatment of which is usually highly successful. Thus, the discussion of the biopsy device of the invention will focus on its use in connection with the analysis of cervical tissue, although it is to be understood that the biopsy device may be used for extraction and analysis of tissue samples in other parts of the body.
Before using a biopsy device to extract and analyze cervical tissue, a doctor will typically conduct an initial screening procedure known as a PAP smear. This screening procedure involves rotating a swab, cytobrush or spatula along the portio cervix or vaginal mucosa to obtain a cell sample which is then spread along a clear slide and analyzed. If the cells appear Atypical with dysplastic features, or reflect low grade or high grade intraepithelium lesions, then a tissue biopsy is usually required.
The most common biopsy device currently used for cervical tissue extraction is a punch biopsy. In order to obtain a tissue sample, a practitioner observes the suspect tissue through a colposcope, which magnifies the tissue, and then uses the punch biopsy to grasp a portion of the tissue and extract it. Major drawbacks of the punch biopsy are that it may cause tissue trauma, disfigurement of the cervix and significant pain. Further, the difficulty in simultaneously using two separate instruments, i.e., viewing the tissue through the colposcope while trying to manipulate the punch biopsy, often results in an inadequate tissue sample. As a result, practitioners often grasp a larger portion of tissue than necessary to ensure that an adequate tissue sample is retrieved. This may result in excessive bleeding requiring cauterization.
One solution to the problem of excessive tissue removal is disclosed by Cibley in U.S. Pat. No. 4,461,305, which is herein incorporated by reference. The Cibley patent discloses a biopsy device comprising a generally cylindrical core-cutter with a rotatably mounted cutting blade. A plunger, slidably mounted within the core-cutter, is used to limit the depth to which the core-cutter advances into the tissue to thereby provide greater control over the sample size. The plunger also provides a means to eject the severed tissue sample. However, it is still possible for the device to penetrate excessively into the tissue. Moreover, like the punch biopsy, this device must be guided using a colposcope.
In addition, both the Cibley device and the punch biopsy are designed for reuse, which is a major drawback in today's infectious-conscious health-care environment where the use of potentially contaminated sharps or other invasive instruments can contribute to the spread of diseases.
Accordingly, the need exists to provide an improved device and method for obtaining tissue samples which reduces the amount of pain and bleeding experienced by a patient.